The invention relates to a method in the operation of an apparatus for producing castings in casting moulds consisting of identical mould parts which are produced successively by the compression of sand or a similar material in a pressing chamber and are from this chamber delivered one by one to a pouring track or guideway on which the casting mould is formed by the mould parts being placed closely together and advanced stepwise through a pouring station.
The functioning of such an apparatus normally comprises three main operations, viz. the production of the mould parts and the transfer of the latter to the pouring track or guideway, the insertion of cores and the pouring of the metal. These three operations are performed in timed relationship with each other, and the maximum capacity of the apparatus, reckoned in the number of cycles per unit of time, is consequently determined by the one of the three operations requiring the longest time. In most cases, this is the operation mentioned first, but according to the circumstances it may also be the insertion of cores or the pouring that is most time-consuming and consequently decisive of the capacity.
Certain types of castings require a comparatively long pouring time, and the present invention deals with the problem of making possible a prolongation of the pouring time for each mould cavity without the capacity of the apparatus being reduced.
With a view to this it is known in advance to let a casting apparatus comprise a mould part producing device in combination with two pouring tracks or guideways, so that the mould parts can from the pressing chamber be transferred alternately to one or the other of these guideways. For a given cycle period for the mould part producing device there will by this means be a period equal to twice the cycle period at disposal for the insertion of cores and the pouring, and the capacity may consequently normally be increased to the limit determined by the cycle period for the mould part production. This possibility has, however, only been created at the cost of considerable extra investments, since two separate pouring tracks or guideways with associated equipment are required. In addition, extra employees for operating and supervising the apparatus must also be included in the costs.